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