The S1 sleep state already shuts the processor clock off and stops the bus clock. Meanwhile Dynamix S3 Sleep is an even deeper sleep state - so your docker files may be saved on your cache drive but with your cpu asleep, they don't run. The only thing you can do in S3 sleep state is getting power from USB 3 ports and wake the system up with a button press on the keyboard or a magic packet (wake on LAN).
If your question was about keeping docker containers running after the system woke up from a sleep, then the "autostart" feature from the docker tab in unraid should help with that, i have not used sleep after i installed a docker that i want to have running 24/7