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