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