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