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