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