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