tactical droid vs clone culture
I was thinking about how General Kalani is one of the only droids with an actual (non-serial number-related) name, and I looked up the super tactical droid wookiepedia page:
and huh! of the four known ST droids, three of them have obviously individual names, and given that their serials would be ST-something, Aut-0 is probably a name too!
(Aut-0's name also seems to demonstrate that he has some sort of sense of humor, and Kraken's paint is suspiciously kraken-looking.)
a bit of further delving found pictures for Kalani, Kraken, and Aut-0 (Linwodo doesn't seem to appear in any visual media).
not only do they all have individual names, they also seem to have unique paint!
now, basic tactical droids do have some distinguishing symbols, but these tend to be simple central lines or logos - just enough to be distinguished.
since ST droids are pretty easily distinguishable from tactical droids (and there'd only really be one on the battlefield anyways), and none of their units have anything similar design-wise, we can conclude that the ST droids' paint is an individual choice.
I doubt Dooku would be busy painting and naming his tactical droids either, so they most likely named and painted each other and themselves...
...much like a certain other batch of beings-not-formally-recognized-as-sentient.