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