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