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