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