This guide is in French, but crucially it has a huge .zip file with what seems to be everything you need. It mentions Graph 75 calculators, but I think it works on 9750GII, the file we need is the SH4 file. Don't quote me on this though as I'm still waiting on a USB cable in the post so I haven't tried it yet. I have the same version as you so I'm also interested in seeing if it works.

http://www.planet-casio.com/Fr/forums/topic13930-1-Ameliore_ta_Graph_35+_USB_E_en_Graph_75(+E)_!.html

Your browser should translate the page from French.