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