Create a new folder called mods in your root folder in your Rockstar Games 
Grand Theft Auto V. Then copy x64v.rpf file from the root folder to the mods folder you just created.
Once that is done you need to have open IV installed with scripthook http://www.dev-c.com/gtav/scripthookv/
Use open IV and go to Mods > x64v.rpf > models > cdimages > streamedpeds_players.rpf > player_one 

1. You can replace the files in the ytd folder by just simply overwriting 
the old ones in Open IV.

2. Or if you don't want all of the haircuts you can go optional and simply
open the ytd files in Open IV and replace the textures with the ones you 
want from the optional folder. 
     