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