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