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