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