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