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