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