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