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