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