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