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