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