Things have moved around quite a bit in this new version. A title banner has been added to the left side of the action bar where the hot dog menu currently resides, and a search icon has been added to the right. Underneath, we see five icons situated where we're used to seeing the Status, Photo, and Check In buttons (which appear to have moved to the bottom). Now there are icons for the News Feed, friend requests, status updates, notifications, and the menu.
Facebook1 Facebook2 Facebook3
Unfortunately, the UI appears to be toggled server-side, where Facebook has control over who gets access. I am unable to see it even after installing the 4.0 APK. Chances are, you might not be able to see it either. But if luck is on your side, feel free to share your results in the comments below
Download - http://d-h.st/lWv
Screen Shots & source - AndroidPolice