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