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