Add a custom CSS class to each of the 3 sections called "inlineSection"

Then, add the following CSS to your form

.inlineSection {
  width:33%;
  display:inline-block;
}

Label/Field widths are percentage based, so you will need to do some more adjustment to make sure they're not too small, but something like the following will target those elements

.inlineSection .cf-label {
    /* adjust label width here if needed, defaults to 20% */
}

.inlineSection .cf-field input {
    /* adjust as needed, the .cf-field container defaults to 75% of*/
    width:95% !important;
}

You may need to use !important to override default styling.

Example of the end results with the sample CSS from above.