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