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