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