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