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