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