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