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