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