I'm afraid that drawing is incomplete and wrong. CC 91 is not master volume - it's the ARP/SEQ Rate control.
You'll find the MIDI CC assignments
here under "MIDI Implementation". For your convenience, here it is:
Function MIDI Message Range
Glide CC 5 0-127
Type CC 9 10-127
Wave CC 10 0-127
Timbre CC 12 0-127
Shape CC 13 0-127
Cutoff CC 23 0-127
Resonance CC 83 0-127
Cycling Env Rise CC 102 0-127
Cycling Env Fall CC 103 0-127
Cycling Env Hold CC 28 0-127
Cycling Env Amount CC 24 0-127
ARP/SEQ Rate (free) CC 91 0-127
ARP/SEQ Rate (sync) CC 92 0-127
LFO Rate (free) CC 93 0-127
LFO Rate (sync) CC 94 0-127
Envelope Attack CC 105 0-127
Envelope Decay CC 106 0-127
Envelope Sustain CC 29 0-127
Keyboard Hold button (toggle) CC 64 0-127
Keyboard Spice CC 2 0-127
Keyboard Pitch Bend Pitchbend 0-127
Keyboard Pressure Aftertouch 0-127