To what extent would filtering out yeast change the color in a beer?
If there is yeast in suspension, then filtering out the yeast will make the beer color appear darker.
When you add yeast, (e.g. when making a starter) the color becomes progressively lighter - the yeast cells make the beer more reflective. When you remove the yeast cells, the beer becomes less reflective, and darker.
The beer will also become clearer, which can affect how some people perceive the color of the beer.
If you filter fine enough, you will also strip out some proteins in the beer, which changes both the body and the color a bit.