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