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)(25,26,29,28)(27,31,35,34)(30,32,38,37)(33,40,36,39)(1,3,4,7)(2,5,6,8)(9,11,14,20)(10,15,17,18)(12,19,13,22)(16,23,21,24)(25,27,29,35)(26,31,28,34)(30,33,38,36)(32,40,37,39)(2,6)(5,8)(26,28)(27,33)(30,38)(31,39)(34,40)(35,36) involution — undirected(9,12,14,13)(10,16,17,21)(11,19,20,22)(15,23,18,24)(25,28,29,26)(27,34,35,31)(30,37,38,32)(33,39,36,40)(9,13,14,12)(10,16,17,21)(11,19,20,22)(15,24,18,23)(27,33)(30,38)(31,40)(32,37)(34,39)(35,36)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.