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