You can't delete it. Look on all your screens and inside all your folders. If you still can't find it go to Settings>General>Reset>Reset Home Screen Layout. This will restore the home screen to its original configuration but may move other apps around to do so.
Sorry, forgot to mention that you can locate Settings by going to spotlight search (swipe the home screen to the right), and typing "Settings" in the search box. Then go to Settings>General>Reset>Reset Home Screen Layout to restore your home screen layout and apps (including Settings).