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