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