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