What you see is the string returned by the toString method of the error object. (error is not a string.)
If a response has been received from the server, the error object will contain the response property:
axios.get('/foo')
.catch(function (error) {
if (error.response) {
console.log(error.response.data);
console.log(error.response.status);
console.log(error.response.headers);
}
});