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