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