As already mentioned, graphs are laid out from left to right by default, but they can be laid out in any orientation you want. This can be configured in the Layout panel of the graph layout tab in the Preferences dialog.
Click "Left to Right" to layout a graph from the left of the screen to the right, as shown in Left to right layout. This is the default orientation for every graph in the environment.
Figure 5.8 Left to right layout
Click "Right to Left" to layout a graph from the right of the screen to the left, as shown in Right to left layout.
Figure 5.9 Right to left layout
Click "Top Down" to layout a graph from the top of the screen to the bottom, as shown in Top down layout.
Click "Bottom Up" to layout a graph from the bottom of the screen to the top, as shown in Bottom up layout.
At any time, you can choose Force Re-layout of Graph from the popup menu to force the graph to redisplay using the current layout method.