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