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