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