Hello,
Cabrillo is a sepcific format for Contest. All Contest programs are able to create the Cabrillo file for the specific contest When working a contest the recommended is to use a good Contest software (such as N1MM, which is free) then create the Cabrillo to submit to the contest manager then afterwards export the contest QSO in ADIF to be imported in Swisslog. This way you have the best of the two worlds!
Check out this website where you will be able to convert your ADIF in Cabrillo:
https://adif2cabrillo.kq4mhe.com/
The DIG number has no specific ADIF field. If the exchange of the contest was the DIG number it will be contained in the RST Received Number field.
73