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