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