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