There is an commented out section of the CommandBox code that enables a Restart Server option in the tray menu. The code can be found in .CommandBox/cfml/system/services/ServerService.cfc currently around line 950.

// serverInfo.trayOptions.prepend( {
	'label' : 'Restart Server'
	,'hotkey':'R'
	,'action' : 'restartserver'
	,'image': expandPath('/commandbox/system/config/server-icons/home.png' )
} );

By restoring the line and restarting CommandBox you'll find a Restart Server option in the tray menu.