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