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