If you have not already done so, insert a chart by selecting it from the Insert menu, or double-click an existing chart to access the chart's configuration panel.
Select the Category Axis tab.
To change the axis color of the category axis, click the Axis Color button and select the new color from the palette.
If you want to show the title on the category axis, select the Show Title check box.
To enter the category axis title, enter the title in the Axis Title box.