It seems to be saying that someone is growing a beard to make themselves look more mature and professional so they can get more respect from others. Someone else is telling him, "That beard won' help you in that regard. Your bad traits will still be obvious. The beard won't hide them for you. It won't make you a better person."

I've not heard this phrase before. But it sounds like it means, facial hair may disguise your facial features but it cannot disguise your bad personality. So, this is an insult, probably made to someone who is growing their facial hair.