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