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