This take on Juggernaut was done by Jack Kirby many years after he stopped drawing X-Men, and gives us a peek at how things might have been if he stayed on the book.
The sketch was printed in "Jack Kirby's Heroes and Villains." From www.whatifkirby.com:
"In the early to mid 1970's, Jack Kirby drew a sketchbook of characters he created and gifted it to his wife, Roz Kirby. In 1987, thanks to Roz Kirby and Greg Theakston, the sketchbook was printed in the hardcover book, "Jack Kirby's Heroes and Villains." It was complete until it was taken a part and individual pages were sold in the mid 2000s."