Not actually a Jumpstart cube: instead, this is a normal cube where the ten two-colored pairs are based on the cycle of legendary creatures from the Jumpstart sets.

WU — Skies
UB — Sacrifice
BR — Minotaur Aggro
RG — Fight
GW — Unicorn Flicker
WB — Lifegain Recursion
UR — Cast From Non-Hand
BG — Insect Graveyard
RW — Ability Chaining
GU — Scry/Sea Monsters