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