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