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