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