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