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