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