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