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