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