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