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