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