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