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