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