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