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