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