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