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