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