Is there any way how to draw a
Fixture from Farseer Physics with XNA?
As I deform these polygons at runtime I can't take any texture from my Content folder, the texture must be generated at runtime too.
You can draw the polygons easily, if you attach the DebugView from farseer, in your physics simulation.
If this is not what you want, you will need to write your own renderer, which is not going to be a trivial task.
You could also extend the DebugView from the Farseer library, seeing as it is open source.