The first time decorated cords are found in the Debris is 1943. Notice the less sophisticated nature of the illustrations and lettering. This image also demonstrates a tradition where the freshman of a fraternity would steal a senior's cords or physically strip the wearer of his cords. Then the freshman would place the cords in a public setting which required the senior to recover the pants and put them on.
The caption for the photograph reads, "Phi Tau seniors come out on the short end of a bet with the frosh."
http://earchives.lib.purdue.edu/u?/debris,23310