If you can find a commercial Cactus mix, that would be the easiest. If not, make a mix of 1 part pumice (best) or perlite (easier to find), 1 part coarse sand or fine aquarium grit, and 5 parts indoor potting compost--most outdoor potting composts contain too much silt or clay to keep cordylines happy. If you like to add a timed release fertilizer, make it a half dose.

I bet you wish you'd never asked, Guest, lol! Multi purpose will do just fine if you can't be bothered with Tugbrethil's suggestion, or John Innes No.2, or a mix of the two.

Just be careful of the watering!