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