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