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