Yes, there are a couple ways to do this.
Each FORM element has an automatically-generated class given based on your form’s name. For example, a form called ‘Volunteer Application’ will have something like ‘volunteer-application’ attached as a class, which you can then use for styling. Search your page source for id=”cforms5form” and you will see which class name was generated.
Alternatively, if your form is embedded in a page or post, you can use the WordPress-generated ‘post-xxx’ class. This obviously only works if you are only using one form in that particular page.
Finally, each field name has it’s own automatically-generated class name that starts with a prefix of the form ID (eg. cf1_field_5 or cf3_field_10) , but they will change depending on the ordering of your fields, so be careful about styling at this level — adding, removing or repositioning fields will require you to change your CSS classes accordingly.
Hope that helps!