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