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