Click an individual curve (or surface in the case of a 3-D plot) in the plot region. The curve becomes highlighted.

From the Plot menu, select Color. Alternatively, select the option in the Context Panel.

Select a color.

The curve is displayed with the selected color.

For three dimensional plots, you can also use shading. For information about shading, see Change Shading.

Note: To change the default colors used for coloring curves in 2-D plots, use the plots[setcolors] command.  To set the default colors for future instances of Maple, put the plots[setcolors] command in a Maple initialization file. See plots[setcolors].