shutdown.exe is located in c:\windows\system32
You can use explorer to right-click and create shortcut, and drag the shortcut to the desktop, or right-click on the desktop, new, shortcut.
In any case you want to edit the "target" of the shortcut by right-clicking and selecting properties. Edit the target line to read:
to force a shutdown: shutdown -f -s
to shutdown with a wait of 10 seconds: shutdown -t10 -s
to reboot: shutdown -r
to force a reboot: shutdown -f -r
You can always do Start, Run, CMD and type shutdown /? to see all available options.