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)(11,17)(12,15)(13,18)(14,16)(19,24)(20,22)(21,23)(25,26,31,32)(27,29,35,39)(28,37,36,33)(30,34,40,38)(1,3,5,8)(2,6,4,7)(9,11,14,12)(10,15,16,17)(13,19,21,20)(18,22,23,24)(25,27,31,35)(26,29,32,39)(28,30,36,40)(33,38,37,34)(1,2,5,4)(3,6,8,7)(10,16)(15,17)(18,23)(22,24)(26,32)(27,35)(28,36)(34,38)(1,2,5,4)(3,6,8,7)(9,10)(11,15)(12,17)(13,18)(14,16)(19,22)(20,24)(21,23)(25,28,31,36)(26,33,32,37)(27,30,35,40)(29,38,39,34)(9,12,14,11)(10,17,16,15)(13,20,21,19)(18,24,23,22)(25,29,31,39)(26,27,32,35)(28,38,36,34)(30,37,40,33)(1,4,5,2)(3,7,8,6)(9,13,14,21)(10,18,16,23)(11,19,12,20)(15,22,17,24)(25,30)(26,34)(27,36)(28,35)(29,33)(31,40)(32,38)(37,39)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.