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