Insert multiple .dat files into one pdf without losing color of their graphs

[zillah]

Dear folk

How can I insert couple of .dat files into one pdf files as without losing the colors of its graph  ? similar to this

https://imgur.com/a/yJy1IQA

Yes I know I can screenshot each individual .dat file as an image then insert them all at once into pdf file but that is length process

https://imgur.com/a/YVrB7aY

Yes I know I can open all these .dat fiels and printer them all at once and they come as one pdf file but I end up losing the colors of the graphs

Thx