The Table Node node type from the "Swimlane Nodes and Table Nodes" palette section uses an alternating color scheme where you can choose two colors that are then applied to the content area rows/columns. Additionally, you can also choose two colors for the header area of the rows/columns. These are also applied in an alternating fashion.
To specify the colors, select a Table Node in your diagram and hit function key F6. On the last tab ("Swimlane Node or Table Node"), you can find the respective options. Alternatively, you can also specify the colors in the Properties View in the GUI after selecting a Table Node.