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