Here are a few different styles of example I use to communicate the Art Direction to the team members.

This was for Scarface 2.

Quick sketch with supporting references and the proposed color swatch for the location.

This is a more complex game mechanic example, with multiple interior sketchs and a 3d geo proposal of the interior layout and references.

These next 3 exteriors, are Art Direction design and supporting reference for colors, I use Maya to help for the construction and communicate the vision quickly.

The following is a paint over done in Photoshop over a screen capture of the game to help in tightning up the look along the way.