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