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