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