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