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