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