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