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