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