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