In your game folder (not in your document folder)
go to The sims 4 / game / bin
backup the file Default.ini in case of.
Then in the original file, replace this section (with notepad or whatever editing program):
[PlumbBob]
playeractivecolor = 0.43, 0.78, 0.12, 1.00 # green
otheractivecolor = 0.00, 0.33, 1.00, 1.00 # light aqua
notactivecolor = 0.00, 0.00, 1.00, 1.00 # blue
npccolor = 0.86, 0.86, 0.86, 1.00 # light gray
interactionnegativecolor = 1.00, 0.00, 0.00, 1.00 # red
interactionpositivelocalcolor = 0.80, 1.00, 0.75, 1.00 # bright green
interactionpositivenonlocalcolor = 0.94, 1.00, 1.00, 1.00 # bright blue
motivestatered = 1.00, 0.00, 0.00, 1.00 # red
motivestateorange = 1.00, 0.50, 0.00, 1.00 # orange
motivestateyellow = 1.00, 1.00, 0.00, 1.00 # yellow
socialgroup = 1.00, 1.00, 1.00, 0.50 # white translucent
by this:
[PlumbBob]
playeractivecolor = 0.43, 0.78, 0.12, 0.00 # green
otheractivecolor = 0.00, 0.33, 1.00, 0.00 # light aqua
notactivecolor = 0.00, 0.00, 1.00, 0.00 # blue
npccolor = 0.86, 0.86, 0.86, 0.00 # light gray
interactionnegativecolor = 1.00, 0.00, 0.00, 0.00 # red
interactionpositivelocalcolor = 0.80, 1.00, 0.75, 0.00 # bright green
interactionpositivenonlocalcolor = 0.94, 1.00, 1.00, 0.00 # bright blue
motivestatered = 1.00, 0.00, 0.00, 0.00 # red
motivestateorange = 1.00, 0.50, 0.00, 0.00 # orange
motivestateyellow = 1.00, 1.00, 0.00, 0.00 # yellow
socialgroup = 1.00, 1.00, 1.00, 0.00 # white translucent
Save and enjoy!
