In this video guide I will show you the locations to be able to get a customized look for Cal, BD-1, and the Mantis. Now before I go any further into this, there is two customization options for Cal.
There is a Poncho and an Outfit. You won't be able to find the outfit until you get to Zeffo. The others you will find plenty of. Once you find one of each, just go to the customization option and equip them to pop the achievement. I will list down below the time stamps for each item.
Poncho - 00:43 - 01: 18
BD-1 Skin - 01:20 - 02:20
Mantis Paint Job - 02:22 - 03:00
Cal Outfit - 03:02 - 03:38