I am not sure what you mean by rendering... I think you meant how you would create a specific shape using Farseer Physics. Using this code:
public static Body CreateBodyFromImage(Game game, World world, string textureName)
//Load the passed texture.
Texture2D polygonTexture = game.Content.Load<Texture2D>(textureName);
//Use an array to hold the textures data.
uint data = new uint[polygonTexture.Width * polygonTexture.Height];
//Transfer the texture data into the array.
//Find the verticals that make up the outline of the passed texture shape.
Vertices vertices = PolygonTools.CreatePolygon(data, polygonTexture.Width);
//For now we need to scale the vertices (result is in pixels, we use meters)
Vector2 scale = new Vector2(0.07f, 0.07f);
//Partition the concave polygon into a convex one.
var decomposedVertices = BayazitDecomposer.ConvexPartition(vertices);
//Create a single body, that has multiple fixtures to the polygon shapes.
return BodyFactory.CreateCompoundPolygon(world, decomposedVertices, 1f);
You will be able to create a custom Body that has the shape of your desired sprite(you can see this in Farseer's Debug View). If you let Farseer handle the collisions then you should get the desired collision as you have described above.
I also recommend taking a look at their documentation: http://farseerphysics.codeplex.com/documentation