General synonyms:
* Hue
* Shade
* Tint
* Pigment
* Dye
* Chromatic
* Tinge
* Coloring
More specific synonyms:
* For bright colors: Vibrant, vivid, bold, brilliant
* For dull colors: Muted, subdued, pale, pastel
* For a range of colors: Palette, spectrum, range, array
Metaphorical synonyms:
* For something that is impressive: Flair, sparkle, brilliance, luster
* For something that is exciting: Life, excitement, vitality
* For something that is beautiful: Charm, appeal, attractiveness
The best synonym for "color" will depend on the specific context of your writing.