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