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