Each color has been "color-shifted" into doing an impression of an enemy color.

White -> Black
White has aggressive removal, sacrifice/reanimator, and a light life drain element, as well as having the most actual colorshifted cards. White counterspells were included for a slightly "meaner" take on control.

Blue -> Red
Blue wants to play aggressively with a low-curve deck. Illusion creatures represent power at cost, and color-break direct damage cards were included. A small number of big mill cards are there as the Blue version of casting a giant fireball to close out the game.

Black -> Green
Black has tokens, ramp, and the largest creatures. It has a lot of combat tricks but little removal and no fliers.

Red -> White
Red has a go-wide tokens theme and a stax/defenders-matter element meant to emulate the controlling parts of White. There are perhaps slightly more cheap fliers than Red usually has.

Green -> Blue
Green here focuses on evasion, card draw, and spells-matter. It's attempting to be a control color.

Gold
The Gold section is doing its best to maintain the color-shifting throughout the cube. For example Azorius (WU) is pretending to be Rakdos (BR). These are a bit of a stretch in some cases, considering the more limited card pool.