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