You have to be outside the orbit of Saturn to see that.
That's incorrect. The shadow can be seen from Earth when the alignment of the planets and the sun is correct. And this shot is clearly taken from within the orbit of Saturn, since more than half of the surface is illuminated.
What is interesting to me is that the angle of the rings is such that the shadow does not go past the edge of the rings, but stops in the middle. I've never seen that before.