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