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