Possible xcode 4.2 bug
This may be because I am just unfamiliar with xcode as I am just starting out. I have been reading through some tutorials and playing around with some options in xcode, and I noticed that if I am viewing my storyboard file and change from standard editor to version editor, the storyboard file reverts to its xml code. When I go back to the standard editor, the xml code remains, and I can not for the life of me figure out how to change it back to the graphical editor. Any ideas?
Try right-click on the storyboard file in the Project Navigator (left side) and select "Open As..." -> "Interface Builder - iOS Storyboard". Definitely a bug in Xcode.
I suggest filing a bug at http://bugreport.apple.com