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