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