How to change the product colours on the product overview?

Q: How to change the product colours on the product overview? For example in the category
Women T-shirts - the point is, that if all T-shirts displayed are in one colour, it looks a bit boring.

A: Just go to Products > Product Sort and choose the category Women T-shirts, add the desired product variants (= colours) and choose the order in which the T-shirts shall be displayed