The only way is to use disk encryption on the swap partition. There are some reports of success doing this... Although this adds another layer of security (assuming you use a different password), you also have to enter and remember both passwords (unless you hardcode it into a startup script, eliminating it's purpose in the first place). Alternatively, you could encrypt the entire drive with a LVM. What the person did was use LVM ontop of a LUKS-encrypted partition (that way you only need a single password).
The reason you have to encrypt the swap partition While they get "erased", the data is still recoverable from the hard drive. Nothing gets erased, it just gets marked as "deleted" as in "next time you want to write some files here, go ahead, nothing is here".
AFAIK, because of these caveats, you're not supposed to use hibernation with LUKS unless you encrypt the entire drive. If you don't encrypt the whole drive, your only other option is to scrub the partition every time you shut the computer down (use a program that will overwrite the data with random bits a few times).