Here is a great example of this iconic singer's multicolored highlights that range from grey to dark brown to blonde.
He goes for the long and shaggy look with defined sections that randomly do their own thing. A coarse wavy texture helps to get a look like this or a defining product with a little finger styling may do the trick. This photo was taken at the 2012 NHL – Pia Toscano and Steven Tyler at the Game Between the Dallas Stars and the Los Angeles Kings