On the X100s, you turned on the grid and picked which one in the Menus, but displaying it was an option of the Displays themselves. Meaning, you turned it on or off per your liking along with Histogram, shots available, aperture setting, shutter speed etc.
I believe it could also be assigned to the Function button to be turned on or off on the X100s but I can't check that since I returned it (rental). I'd assume it would be similar on the other X series.
I just downloaded the X-M1 manual and did a quick look at it...
Page 72-73 covers the basics of the Grid function. It appears it can be turned on and off in Disp. Custom's settings. On Page 19, the info for it is noted there for the Custom Display and Disp/Back button. You cycle through the 4 displays with Disp/Back: Information 1, Information 2, Information OFF and then Custom. Custom is where the grid would be displayed, based on which one you picked.
There are 3 Grid settings, Grid 9 which is a Rule of Thirds grid, Grid 24 which is 6x4 and HD framing which displays lines top and bottom to frame out an HD sized frame in the display.
The manaul is here:
http://www.fujifilm.com/support/digital_cameras/manuals/pdf/index/x/fujifilm_xm1_manual_en.pdf
I find it handy to have the many on my phone or in my Dropbox for my gear for easy searching for questions. I tend to end up needing info in the field and rely on it quite often to be in my pocket brain.
