You can change the canvas background color in Wovex. 

This can be done in two ways: Right click on the canvas, select Map Background and Change Color or go to the Design tab, click Map Color and select the color you wish the canvas to be. 

Note that if you change the color of the canvas and print your model your selected color will be printed.

You can reset the color to default by right clicking the canvas, selecting Map Background and Reset Color or in the Design tab in Map Color choosing a No Formatting option.