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