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