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