Hi,
You can add the CSS from this example (you might want to shrink it a bit I think): https://www.w3schools.com/howto/howto_css_switch.asp to your Custom CSS and then add this to your Custom JS:
jQuery("#dffs_YOUR_FIELD_NAME").find("input").wrap("<label class='switch'></label>").after("<span class='slider round'></span>");
Replace YOUR_FIELD_NAME with your actual field name.
Alexander