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