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