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