How can I rename a Logical Volume Group?
If you have Yosemite installed, diskutil now includes the option to rename a Core Storage logical volume group (LVG) from the command line:

$ diskutil cs rename
Usage:  diskutil coreStorage rename lvgUUID|lvgName newName
Rename a CoreStorage logical volume group. Do not confuse this with LV names.
Ownership of the affected disks is required.


So use diskutil cs list to get a list of your Core Storage volumes, then diskutil cs rename "Crucial M4 SSD" newVolumeGroupName to rename the LVG.  

I haven't tested this on a mounted volume, so I don't know if you can do it without unmounting the volume. That may mean that you need to boot off an external disk with Yosemite installed in order to rename the LVG.