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)(11,22)(12,28)(13,30)(14,21)(15,20)(16,19)(17,26)(18,34)(23,32)(24,40)(25,36)(27,37)(29,39)(31,33)(35,38)(1,2)(3,5)(4,6)(7,8)(9,11)(10,17)(12,29)(13,32)(14,25)(15,26)(16,27)(18,38)(19,36)(20,22)(21,37)(23,31)(24,33)(28,35)(30,40)(34,39) involution — undirected(1,3,4,7)(2,5,6,8)(9,12,15,18)(10,13,20,33)(11,23,26,40)(14,30,16,31)(17,35,22,39)(19,28,21,34)(24,37,32,36)(25,29,27,38)(2,6)(5,8)(9,13)(10,18)(11,24)(12,20)(14,28)(15,33)(16,34)(17,29)(19,31)(21,30)(22,38)(23,37)(25,39)(26,32)(27,35)(36,40) involution — undirected(9,14,15,16)(10,19,20,21)(11,25,26,27)(12,30,18,31)(13,28,33,34)(17,36,22,37)(23,29,40,38)(24,39,32,35)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.