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