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