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