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