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