the graph isn't messed up. looks like an infinitely oscillating function to me, which by its nature is hard to display graphically. if you zoomed in enough (a TON) you would see a bunch of lines going up and down.
if you look closely, on the left end of the graph you can see a few lines up and down - as the function goes towards the right they quickly get closer and closer. close enough that it just looks like a big blue blob.