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