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