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