I had mine disappear on me one day and thought I was losing my mind.
A reboot made it reappear again.
Quite odd so if you don't see the settings as above reboot and look again.
As a general approach: you might want to use the system-wide search when you are looking for something. I tend to do that, especially when I'm looking for some specific settings. I like that it takes you directly to the right setting instead of going from category to subcategory and so on...
Thanks guys. Yeah it wasn't there when I went through the settings which I thought was quite weird, didn't even come up when I did the system search. Did a reboot and it magically appeared, don't know why that happened? :S