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