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)(11,19)(12,25)(13,15)(14,28)(16,24)(17,27)(18,21)(20,29)(22,36)(23,33)(26,39)(30,35)(31,38)(32,37)(34,40) involution — undirected(2,5)(6,7)(10,15)(11,20)(12,26)(14,21)(16,19)(17,30)(22,37)(23,24)(29,33)(31,32)(34,38)(36,40) involution — undirected(9,11,21,20,13,23,14,24)(10,16,28,33,15,29,18,19)(12,22,35,34,26,38,27,37)(17,31,39,40,30,36,25,32)(9,12,14,27,13,26,21,35)(10,17,18,25,15,30,28,39)(11,22,24,37,23,38,20,34)(16,31,19,32,29,36,33,40)(1,3,4,8)(2,6,5,7)(10,15)(16,29)(17,30)(18,28)(19,33)(25,39)(31,36)(32,40)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.