By default, Excel creates all pivot charts on their own worksheet. However, you can get around this default and create a pivot chart on the same worksheet as your pivot table.
Place your cursor in a cell outside your pivot table and launch Excel's Chart Wizard. In step 1 of the wizard, select the type of chart you want to use. In step 2 of the wizard, click on your pivot table and then click Finish. A new pivot chart will be created on your worksheet, just as a normal chart would. All you have to do at this point is format the chart.