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