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