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