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