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