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