The only information that can be displayed on the Tournament page, the Player Rankings page, or the Seating Chart page, is information about the currently loaded tournament. League rankings are calculated over many tournaments played, so this info cannot be (directly) placed onto the Tournament Director screen.
You can export this information from the Stats page to an HTML file, and then do with that as you want. As Matt pointed out, you can reference that file using a rules token, and place the rules token on one of your layout screens, and voila - league rankings.