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