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