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