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