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