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