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