You can disable it with this css

.grecaptcha-badge {
    display: none;
}

BUT, to remain compliant with the google terms of service you must include this with your forms using it (in the users flow), so under the form submit button would be a good place):

<small>This site is protected by reCAPTCHA and the Google 
    <a href="https://policies.google.com/privacy" target="_blank">Privacy Policy</a> and <a href="https://policies.google.com/terms" target="_blank">Terms of Service</a> apply.
</small>