This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
The last time I needed to draw an inner class into a class diagram (which was a long time ago), I ended up using the same class notation for both inner and regular classes. If the inner class is non-static, you can associate it to the outer class using a composition. Otherwise, I would just rely on the name ("MyOuter.MyInner") to communicate my intention. However, I would be interested to know what others think about this as I really didn't do much research on existing practices at the time.