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