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