As Erik mentioned, Daedalus is a full node and thus requires downloading the chain from peers and validating it locally on your machine. However, if you already have a trusted copy of the chain (either from previously syncing a full node or some other source), you can manually copy it into Daedalus' state directory. Doing this will speed things up because Daedalus will only have to validate the provided chain instead of downloading the whole thing from genesis. Of course, it will also have to download whatever is needed to extend the provided chain's tip to the current tip.
First, launch Daedalus, and click on Help > Daedalus Diagnostics. Under the "Core Info" section, the "Daedalus State Directory" specifies the filepath that Daedalus uses on your computer. In this directory should be a folder titled
chain, containing 3 subdirectories:
volatile, as well as 2 files:
Next, shutdown Daedalus, then replace the 5 assets in the
chain folder with the other 5 found in your local copy of the chain (they should all have the same filenames as mentioned above). Also, make sure the
chain folder and files have appropriate permissions (chmod 775 for
Restart Daedalus and enjoy a faster sync!