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