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