color border

Format Menu, select cell, click on the border tab. There is a drop down box, lower left quadrant, from which to select color.
Richard

Right click on the cell that you want to color, select format cells.

select border

select the line style that you want, under that you will see a box that says color, click in there and select the color that yo want. Then select the proper sides (or outline so all sides of the cell are covered) and you now have a cell with a colored border.