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)(11,15)(12,14)(13,16)(17,19)(18,23)(20,21)(22,24)(25,26)(27,32)(28,30)(29,36)(31,34)(33,39)(35,37)(38,40)(1,3,5,8)(2,6,4,7)(9,10,14,12)(11,17,19,15)(13,16,21,20)(18,24,22,23)(25,27)(26,32)(28,36)(29,30)(31,35)(33,38)(34,37)(39,40)(1,2,5,4)(3,6,8,7)(10,12)(13,21)(15,17)(18,22)(27,35)(29,39)(32,37)(33,36)(9,11)(10,15)(12,17)(13,22)(14,19)(16,24)(18,21)(20,23)(25,28,31,38)(26,30,34,40)(27,33,35,36)(29,32,39,37)(1,4,5,2)(3,7,8,6)(9,12,14,10)(11,17,19,15)(13,20,21,16)(18,24,22,23)(25,29)(26,33)(27,30)(28,37)(31,39)(32,38)(34,36)(35,40)(9,13)(10,16)(11,18)(12,20)(14,21)(15,23)(17,24)(19,22)(25,30)(26,28)(27,29)(31,40)(32,36)(33,37)(34,38)(35,39) 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.