To show the pointer on the Presentation Window, press the C key or select Presentation → Show Pointer. If you go over the current slide in the Presenter Window with your cursor, the pointer will appear at the same position on the Presentation Window. To hide the pointer, do the same as showing the pointer.
Note: This works in the normal layout (where notes are not displayed in the Presenter Window) but it also works when the notes are displayed. Therefore, just like before, go with the cursor over the (smaller) current slide preview in the Presenter Window and the pointer will magically appear on the Presentation Window.
You can change the appearance of the pointer by going to Presentation → Pointer Appearance and select one of the given options.
By selecting Individual, you can use a customized pointer. To customize the pointer, open the Pointer Editor.