When you run git log --decorate --pretty=oneline the output will have entries like (HEAD, refs/published/master, master) with coloration.
git log --decorate --pretty=oneline
(HEAD, refs/published/master, master)
I
Parenthesize them:
%C(...): color specification, as described in color.branch.* config option
So %C(yellow reverse) would work.
%C(yellow reverse)