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