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