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