There is a technology called hair coloring, stack it with a hoodie and some well fitted slacks, roll up one of the ankle cuffs a bit. Talk like you've exited a startup and are just working for fun, or something to keep you interested, but not like you actually have to.
Absolutely not. This is idiotic advice. I'm not paid to be pretty. I earned this gray beard and if you don't respect the years of experience it represents, you and your hipster brogrammer culture can fuck right off.
However when it comes to advice, are we interviewing for a job in an imaginary world, or the real one?
If it's the real world, this is great advice. Just like having a marketing team instead of thinking every product will sell itself is great advice that almost every company in existence learns at some point or another.