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