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