Show in navigation if user is not logged in

Just Follow Below Steps:- 1)Select Document 2)Select Property Tab 3)Click on Security tab 4)In that you can find "select role" 5)click on that and select role from it. name of role is "unauthorized" 6)And save it and test it.....

In case your page menu is represented by some web part I recommend you to set Visibility property of the web part to macro expression {% !CurrentUser.IsAuthenticated |(identity)GlobalAdministrator%}

better Solution....