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