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