I recently got after affects and I have been trying to use graphs but it doesn't show up. I tried scrolling, pressing the "fit all graphs to view", highlighting my keyframes, so maybe i'm just missing something.
You have to have a keyframed property selected in the timeline for anything to show up in the graph editor. The cropped screenshot is useless for diagnosing your problem but I'm positive you do not have a property that has keyframes selected.
Speed graphs are useful for adjusting the timing of position properties, rotation, scale, even color, and sometimes time-remapping depending on what you are doing with time remapping. . Value graphs are useful for rotation, scale and that's about it. Value graphs are completely useless when it comes to editing a motion path.
Maybe this tutorial I recently put up will help you understand and use the Graph Editor effiectively. There are more tutorials on the Graph editor on the way.