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