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