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