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