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