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