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