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