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