An example in my lecture notes says, 'draw a simply connected covering space over the figure eight'.
Howerver, after googling, wikipedia tells me that ''The universal cover of the figure eight can be visualized by the Cayley graph'' but I can't see how this graph is simply connected?
NOR, how I am supposed to draw it?
Is there a simple 'draw-able' universal cover of the figure-eight?

The universal covering space is unique up to homeomorphism. Remember the fundamental group of the figure 8 is the non-commutative free group on two elements. Hence the complex appearance of its covering space.