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