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