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