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