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