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