The Graphics tab of the SubModel dialog provides access to options for controlling the appearance of elements inside the SubModel:
The top portion of the dialog (the Graphics Pane section) is used to define the size of the graphics pane, a background color for the graphics pane, and whether or not a grid is displayed.
The bottom portion of the dialog (the Influences section) is used to specify the default shapes for influences in the SubModel, and to define whether and in what manner influences within the SubModel are filtered (hidden). The options in this portion of the dialog are quite important, as they can be used to ensure that your models are easy to view and understand.
Learn more about:
Adjusting the Size of the Graphics Pane
The Graphics Pane Grid and Background