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)(11,20,24,16)(12,25,29,36)(13,19)(14,30)(15,18)(17,27,34,28)(21,38)(22,35,23,32)(26,37)(31,39)(33,40)(2,6)(3,4)(7,8)(9,11)(10,16)(12,26)(13,23)(14,22)(15,24)(17,33)(18,20)(19,35)(21,28)(25,31)(27,40)(29,39)(30,32)(34,38)(36,37) involution — undirected(2,7)(3,4)(9,12)(10,17)(11,21)(13,28)(14,27)(15,29)(16,31)(18,34)(19,36)(20,37)(22,26)(23,39)(24,40)(25,30)(32,38)(33,35) 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.