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