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