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