You probably don't need a MIDI cable, just a USB cable
The Axiom has a USB cable jack. The regular way of hooking up your Axiom to your computer is with a USB cable. You don't need a MIDI cable unless you are going to hook up some old gear that has a MIDI jack and no USB jack.
When they talk about using MIDI, it means using "computer code between things". It doesn't always mean you are going to be using a MIDI cable.
MIDI cables used to be called DIN cables. In the 60's and maybe before, some companies used them for connecting tape recorders to amps. It gave you stereo in and out in one cable.
Radio Shack's MIDI cables look like Hosa and that's what I use to hook up gear I have from the 80's.