These answers are on the right track, but I think headed the wrong way. The picture in the I&T maual is the wrong direction.
Keep in mind that (as Donny pinted out while I was typing this) the shaft and slinger (actually impeller) are stationary. When it is in place on the shaft, if you place your finger at the tip of the impeller and slide it along the impeller clockwise (the direction the oil is rotating) it should move towards the shaft.