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