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