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