Do you mean during playback (on camera)?
It should be visible in playback mode by pressing the "Info" button until you get to the screen with the image + histogram + info - the image preview should show the focus point as a green point/square.
If that screen doesn't come up when cycling through by pressing "Info", it might be turned off in your display settings.
This is done in the main menu, playback tab, page 3 (Displays), <play icon> info settings.
The option labelled "overall" needs to be checked on.