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