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