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)(11,18)(12,17)(13,20)(14,21)(15,24)(16,27)(19,30)(22,36)(23,34)(25,32)(26,38)(28,35)(29,37)(31,39)(33,40) involution — undirected(2,5)(6,8)(9,11,13,24,14,26,30,25)(10,15,19,18,21,32,20,38)(12,23,27,39,29,40,28,22)(16,33,17,31,35,34,37,36)(1,3,4,7)(2,6,5,8)(9,12,13,27,14,29,30,28)(10,16,19,17,21,35,20,37)(11,22,24,23,26,39,25,40)(15,31,18,34,32,36,38,33)(9,12,14,29)(10,17,21,37)(11,23,26,40)(13,27,30,28)(15,31,32,36)(16,19,35,20)(18,34,38,33)(22,24,39,25)(9,11)(10,18)(12,22)(13,24)(14,26)(15,20)(16,34)(17,36)(19,32)(21,38)(23,27)(25,30)(28,40)(29,39)(31,37)(33,35) 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.