As said can drop anywhere. Basically set your game to whatever difficulty you can crush through. Then farm rifts until you're ready to kill yourself. Then, take a break, rinse.. repeat.
Alternatively you could set the difficulty to anything lower than torment, as maximus is not a torment locked item, thus removing all torment locked items from the loot table of possible drops you'll get.
Here's one I found and actually kept. Life per kill, 1k+ str and almost maxed +fire dmg earned it a spot in my stash
http://us.battle.net/d3/en/profile/Moltres-1908/hero/44882667
http://imgur.com/8NVKtJy
Alternatively you could set the difficulty to anything lower than torment, as maximus is not a torment locked item, thus removing all torment locked items from the loot table of possible drops you'll get.
edit: didn't get the picture to show