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