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