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