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