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