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