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