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