The article provided by @dverhey is interesting. It suggests that all you need to do is change the set-up before you even run. I would accept that doing all that it says is true… and likely could cut a good half second from your times. However, you may not have the option to start from 3 point and you will still be competing with folks who are still a good second faster than you.
All my experience has been as a distance runner (1–2miler on track), so what we did to gain speed may not apply… what we did though was do fartlek workouts. We would run varying lengths of distance at a sprint with a short jog in between. The other speed workout we did was to do 8–10 sprints of 220 or 440 yds with recovery of 100 yd jogs in between.
For a shorter distance you could do 10 yds at your fastest speed with 5yd recovery through the 40 yds. Another thing to try is change your stride length. A lot of folks try to sretch their stride too long. For short sprints take shorter strides. Not too short, just enough that you get more power driving through the entire distance. Also don’t forget to move drive your arms as much as you do your legs… as your legs have to be synched with your arms as you stride. If they are lagging your stride can only go so fast. Last for a distance like 40 yards you should be up on your toes the whole way. If you are hitting heels at any point you will be slowed down.