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