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