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