Colors of lexical categories?

Hello!

I’m currently planning an visualization method for presenting language, and what i had in mind, is to differentiate parts of phrases, i e the lexical categories, or word classes with different colors each.

Before i go too far, i’d like to ask if some allready had made this before?

When i was “still young”, at the early years in school, we used to underline verbs and nouns in phrases with blue and red.

How would you colorize the rest (or if there is some other systems?):

verbs - blue
substantives - red
adjectives - ?
particles - ?
adverbs - ?
numerals - ?
prepositions - ?

maybe using a RGB+CMYK fashion

verbs - blue
substantives - red
adjectives - green
particles - cyan
adverbs - mangenta
numerals - yellow
prepositions - bold black (or gray)

of course you can change a little