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