One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,4)(3,7,8,6)(9,10,15,19)(11,20,23,16)(12,13,24,17)(14,18,22,21)(25,26,32,38)(27,35,29,33)(28,36,30,34)(31,37,40,39)(1,3,5,8)(2,6,4,7)(9,11,15,23)(10,16,19,20)(12,21,24,18)(13,22,17,14)(25,27,32,29)(26,33,38,35)(28,39,30,37)(31,36,40,34)(9,12,15,24)(10,17,19,13)(11,21,23,18)(14,20,22,16)(25,28,32,30)(26,34,38,36)(27,37,29,39)(31,33,40,35)(1,2,5,4)(3,6,8,7)(9,12)(10,13)(11,21)(14,20)(15,24)(16,22)(17,19)(18,23)(25,29,32,27)(26,35,38,33)(28,37,30,39)(31,34,40,36)(9,13)(10,12)(11,22)(14,23)(15,17)(16,21)(18,20)(19,24)(25,30,32,28)(26,36,38,34)(27,37,29,39)(31,33,40,35)(1,4,5,2)(3,7,8,6)(9,14,15,22)(10,18,19,21)(11,13,23,17)(12,20,24,16)(25,31)(26,37)(27,36)(28,33)(29,34)(30,35)(32,40)(38,39)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.