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