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