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