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