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