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