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