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