One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,7,8,5)(9,10)(11,15)(12,16)(13,21)(14,17)(18,24)(19,22)(20,23)(25,26)(27,32)(28,39)(29,44)(30,35)(31,34)(33,41)(36,53)(37,49)(38,47)(40,46)(42,51)(43,52)(45,48)(50,54)(55,56)(1,3,4,8)(2,5,6,7)(9,11)(10,15)(12,19)(13,18)(14,20)(16,22)(17,23)(21,24)(25,27)(26,32)(28,40)(29,37)(30,45)(31,38)(33,50)(34,47)(35,48)(36,42)(39,46)(41,54)(43,55)(44,49)(51,53)(52,56)(11,18)(12,13)(15,22)(16,21)(19,20)(23,24)(25,28,31,43)(26,33,34,51)(27,36,38,54)(29,42,30,41)(32,46,47,56)(35,52,44,39)(37,55,45,40)(48,50,49,53)(9,12,14,13)(10,16,17,21)(11,19,20,18)(15,22,23,24)(26,34)(32,47)(33,51)(35,44)(39,52)(46,56)(48,49)(50,53)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.