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