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