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