Unfortunately, there is no way to start a program from where it left off after a power loss or stop. However, if you previously homed the machine prior to the pause, you can recover the XY work zero position to save your material by homing the machine once you've reconnected and when setting the XY work zero position, hit the "USE LAST XY" option.
We have a guide on this here:
This will only work if you have used the homing switches or marked a starting point on your project.
You may also duplicate your workpiece and delete any parts of the design that were already carved to save time. Alternatively, you could "mask" parts that have already been carved on your project by placing a white (0" depth) square or other shapes on top of shapes that have already been carved. You'll need to ensure your work zero is set to the same starting point as the initial carve.