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