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