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