https://www.lodev.org/jstumble/?board=10r10lerxlfrlfexferlfexferlfexferleex_8_8
The part count can be optimized by using crossovers to combine the return paths.
Start the machine using the blue lever. Alternatively, you can use the following solution, but this time starting the machine using the red lever:
https://www.lodev.org/jstumble/?board=11r11lerxlfrlfexferlfexferlfexferleex_8_8