Not your typical "Mercury is blue, Mars is red" type senshi color page.  Well, maybe it is, but this page also has information on why the colors were chosen (not just fuku colors, but hair and eye colors also).


Moon's color is pink.  Her fuku is blue and red, but her color is pink because that's what color she glows during the Sailor Planet Power.  The pink probably represents purity, love, or femininity.  The blue on her fuku...well, probably because blue is Naoko's favorite color and Usagi is based on her ^_^  I've also seen both blue and red used to represent love, so maybe that's why red was also used.  Her other color is silver, like the silver crystal, and because as a princess in the manga her hair was silver.  This is because the moon looks silver sometimes, I guess.
Chibimoon's color is also pink.  This could be because Moon's color is pink and maybe it's an inherited thing.  Pink is also used to represent young girls (you know how Barbie always wears pink?), and Chibiusa is a young girl.  It could also represent the same things that Moon's pink does (femininity, love, purity, innocence...).
Well, gee.  Mercury's fuku is blue, her hair is blue, her eyes are blue, her princess dress is blue, and she always wears blue except for in her civilian form sometimes.  Maybe her color is blue? ^-^ Obviously, the blue represents water, and Mercury controls water. 
Mars's colors are red and purple.  Her fuku is mostly red, and her princess dress is red, plus her school fuku is partially red, if I remember correctly, and she wears red often in normal form.  The red represents fire, which is her element, and also possibly because Mars is the red planet (it's red, and that's what people call it also).  The purple probably doesn't represent anything specific, it was probably just used because it looks good with red.  Purple is used on the bows of her fuku, and her hair has purple-ish highlights.
Jupiter's color is green in the anime, pink in the manga.  Her fuku is mostly green, with the bows being pink.  Her hair bobbles are green too, and so are her eyes.  Plus she mostly wears green, except for her earrings which are pink.  The green could be because her element is wood and trees are green.  Her hair is brown, this is probably part of the wood thing too since wood is brown.  The pink most likely represents her feminine side, and the green...maybe her masculine side? 
Venus's color is gold.  Her hair, attacks, some of her civilian clothes, her princess dress from the manga, and parts of her fuku are all gold.  Well, the back bow of her fuku is, the rest of it is mostly orangish-gold.  Except for her front bow which is blue (her bows don't match), and her eyes are blue, that could represent love.  Anyway, the gold probably is because Venus the planet is a yellowish color (there's sulfur and other poisonous stuff in its atmosphere), and it's called kinsei in Japanese, which means gold star.  Her hair bow is red (the story is that the guy she had a crush on in the Sailor V manga said she'd look good in a red bow so she's worn one ever since), and red represents love too (as I mentioned with Moon).  She and Moon have some of the same colors, this could be because of their similar personalities.
Pluto's color is dark red.  Well, at least I think so.  Either that or it's dark grayish black like her fuku color.  Her eyes, her talisman (the Garnet Orb), the brooch on her fuku, the dangly garnet on her choker, and her earrings (which are probably also garnets) are dark red.  Well, the jewels are dark red because that's what color garnet is.  Dark red is the color of blood, maybe because Pluto was the Roman god of death (or at least the underworld).  The blackish color on her fuku could stand for, like, oblivion or something like that.  Her hair is green, and I really don't see the symbolism in that (though it looks good, but that's beside the point).
Neptune's color is sea-green, like on her fuku.  Her fuku, her hair, her eyes, her princess dress, and some of her civilian clothes are some variation of sea green.  This is because she is the senshi of the ocean.  And her other color is dark blue, becuase that's the color of the ocean depths (and water in general is blue, so..).  Her bows are blue and some of her civilian clothes too.
Uranus kind of has two colors: gold and dark blue.  Her princess dress, her eyes, and part of her fuku is blue; but her bow and her hair in the anime are gold, and during the Planet Attacks she glows gold.  But I guess her main color is blue.  The blue could possibly represent the sky (since that's what she's the senshi of, and Uranus in the Greek myths represented the sky).  And the gold...I don't know, the sun?  The sun is, after all, in the sky.  Another reason why she may have dark blue is because dark blue is also one of Neptune's colors, so having them both have the same color could represent how close they are.
Saturn's color is dark purple.  Her fuku is mostly dark purple, and she has that color highlights in her hair, and her princess dress is purple, so are her eyes, plus she sometimes wears that color in her civilian form.  Her hair is black, which represents death in the Western culture.  She also has pale skin, which, I hate to say this but, may have been used to make her look, like, dead or something.  You know the expression "deathly pale"?  Besides, her element is death.  The dark purple was probably used because it looks good with pale skin and dark hair, not that it means anything.  She also has that star-shaped white crystal on her fuku, and white represents death in Eastern culture (well, Chinese culture, I'm not sure about all other Eastern ones).  Her bows are brownish colored, and the planet Saturn is called dosei in Japanese, which means "soil star", and soil is brown.