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