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