Executing this query is psql does not give the error: Invalid input syntax for UUID: uuid_generate_v4(),
This query is almost correct except you have a trailing comma in your VALUES statement that is going to provoke: syntax error near "," (i.e., you haven't provided a value for cashier_phone_number)
The query, which you have not yet shown, that provoked the "Invalid input syntax for UUID: uuid_generate_v4()" must have had the function call specified within single quotes in order for the server to think it was a literal value instead of an expression to be evaluated.