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