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