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