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