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