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