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