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