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