The line landing in little s's will actually be a useful skill down the road, but for now, you're best off knowing what's causing it. Those squiggles are caused by the line bouncing back after an over-powered cast turns over, and the extra power puts vibrations into the line. Just back off the power a little bit, do everything else the same, and you should see the line straighten out more.
There's another possibility- you might be gripping the rod so tightly after you come forward and stop, that the rod is continuing to vibrate at the tip and put those squiggles in the line. If this is the case, try this- right after you come forward and come to a positive stop, ease your squeeze on the cork enough to where the rod tip drops a small amount and quits wiggling. Your cast will improve, and your wrist will thank you.