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