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