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