Well, yes. Unless you have setup sudo so it doesn't ask for password, then use sudo. It's nothing special, just
#!/bin/sh
kdesu -c '66-stop bluetoothd'
or
#!/bin/sh
sudo 66-stop bluetoothd
Save that to some file, for example $HOME/bin/turnoffbt (you will need the directory $HOME/bin created with mkdir $HOME/bin if it doesn't exist), chmod 755 it (which will give it execute permission, more info: man chmod):
chmod 755 $HOME/bin/turnoffbt
and add it to shortcut.