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)(11,15,21,29)(12,16,25,33)(13,17,24,32)(19,27,36,39)(20,28,26,34)(22,30,35,38)(23,31,37,40)(2,4)(5,7,8,6)(11,19)(12,22)(13,24)(15,27)(16,30)(17,32)(20,37)(21,36)(23,26)(25,35)(28,40)(29,39)(31,34)(33,38)(6,7)(9,11,14,21)(10,15,18,29)(12,23,25,37)(13,26,24,20)(16,31,33,40)(17,34,32,28)(19,35,36,22)(27,38,39,30)(2,4) 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.