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