Saca los colores

Saca los colores
 

Does anyone know what this may mean? I was in a headline about the
Wall Street embezzler Madoff. "Madoff saca los colores al reguladores."

shows his true colors? just guessing

Madoff embarrasses the regulators.
Sacarle los colores = to embarrass someone

OK.In Spanish it's: Leaves their faces pale as opposed to turns their faces red which we are more likely to use. Thank you.

One of the many meanings of sacar is to bring out, so it means to bring out the colors.

It would be interesting to know the etymology of this phrase.