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