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