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