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