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