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