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