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