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