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)(11,12)(13,17)(14,15)(16,18)(19,20)(21,22)(23,24)(25,26,31,32)(27,29,28,33)(30,34,38,39)(35,37,36,40)(1,2,4,6)(3,5,8,7)(9,10)(11,18)(12,16)(13,17)(14,15)(19,22)(20,21)(23,24)(26,32)(27,28)(34,39)(35,36)(1,2)(3,5)(4,6)(7,8)(10,15)(11,16)(17,24)(19,21)(25,27,31,28)(26,33,32,29)(30,35,38,36)(34,40,39,37)(1,3,4,8)(2,5,6,7)(9,11,14,16)(10,12,15,18)(13,21,23,19)(17,22,24,20)(25,28,31,27)(26,29,32,33)(30,36,38,35)(34,37,39,40)(9,12)(10,16)(11,15)(13,22)(14,18)(17,19)(20,23)(21,24)(25,29)(26,27)(28,32)(30,37)(31,33)(34,35)(36,39)(38,40) involution — undirected(9,13,14,23)(10,17,15,24)(11,19,16,21)(12,20,18,22)(25,30,31,38)(26,34,32,39)(27,35,28,36)(29,37,33,40)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.