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