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