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