Why are there different color scripts?
In television and film, colored pages are used to track script revisions as they progress into production. The color of the page indicates which revision it is, allowing script supervisors to quickly identify which pages have been changed and which version they are reading.
The X-Files scripts order is the following:
White Draft, Blue Revision, Pink Revision, Green Revision, Yellow Revision, Goldenrod/Gold Revision, Salmon Revision, Second Blue Revision, Second Pink Revision, Second Green Revision, Second Green Revision, Second Yellow Revision, Second Goldenrod/God Revision, Second Salmon Revision