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