What colour are Krieg vehicles usually painted?

It varies from individual regiment to regiment - the Forge World Vraks books has 10-20 different Krieg colour schemes that fought in campaign on the planet.

It's basically realistic military / camp sort of colours - grey, green, brown, tan and black are commonly used. Sometime with camo patterns of some kind.

Some example photos from the Vraks books are on FW's site:

Thanks. I forgot about the examples from the IA books on the FW site.