Can you roll over 457 into a roth IRA?

Yes, if the Roth is being transferred from one firm to another, then it is just a transfer. Simply request an account transfer form from the receiving institution, fill it out, and submit with a copy of a recent statement. If this is happen from Roth IRA to Roth IRA within the same firm, then this is just consider a consolidation. Neither of the above mentioned scenariOS would result in any tax consequences/penalties.