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