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