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