One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10,13,16)(11,14,18,23)(12,20,21,15)(17,24,19,22)(25,26)(27,36)(28,40)(29,34)(30,45)(31,35)(32,38)(33,43)(37,50)(39,48)(41,53)(42,52)(44,51)(46,49)(47,55)(54,56)(2,5)(6,8)(9,11)(10,14)(12,17)(13,18)(15,22)(16,23)(19,21)(20,24)(25,27,29,38)(26,32,34,36)(28,41,42,55)(30,39,31,46)(33,50,51,56)(35,48,45,49)(37,43,54,44)(40,47,52,53)(11,17)(12,21)(14,22)(15,20)(18,19)(23,24)(25,28,29,42)(26,33,34,51)(27,37,38,54)(30,44,31,43)(32,47,36,53)(35,52,45,40)(39,55,46,41)(48,50,49,56)(1,3,4,7)(2,6,5,8)(27,38)(32,36)(37,54)(39,46)(41,55)(47,53)(48,49)(50,56)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.