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