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