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