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