Frayed cords on my AC power adapter

my AC power adapter has had a hard 3 years. I want to replace the cords rather than buy a new power adapter because I might be buying a new laptop in the near future. I've spliced the cords to new cords but it is ugly, I want to open the plastic case and solder new cords directly to the power adapter. The problem is, I don't see any way to open the plastic case....any one know how it comes apart or has a good diagram? I would like to keep the power adapter in tact as much as possible. PS. greetings (first post)