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