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