F1 22

from the menu, to F1 Life.
on Customisation and to Player Car Liveries.

chose your design to edit or create a new one, and from here, select the Liveries option.

to change the color on your design (or any random design). or to reach Paint Finish.

or to change it from what it was (Metallic, Matte, Satin or Gloss).

to the next color and do the same thing. once all colors on the design have a changed paint finish, the achievement should pop

(if it doesn't, accept the changes with and that should trigger it).