Just go talk someone somewhere around the map. You first tell to that player which part you would let them change.
For example, you say "Body Color?", then they will take their time to find out which color fits best.
My skin color is hex code #FFDAB7 or beige (Hex or Color name)
They will either say, for example, "light blue" which corresponds to #27CBFE.
Be careful for some colors that will NOT blend well.
You'll do the same for horns and/or wings, front mane, back mane, etc.