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