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