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