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