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