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