Well, the file/picture I got is a six-sided version and did not open, am trying other things... don't think it was operator error on Kalama's part. I know I have how to do this as a hex in a book -- just have to look for it.
If someone has a book on octagon or hex variations, it should be findable maybe even with directions. I know the book I have is just diagrams with no construction info.
I can always finalize my rough sketch if you give me a desired finished block size. I'd be starting with my triangle ruler and cut out the 8 triangles of background fabric. Then I'd put one each color bar on either side of four of the triangles (you can make them with the pointed tops), and then put the corner triangle across that diagonal edge. I'd then combine each corner with a center triangle, piecing them around the block and as mentioned before leaving that center octagon to applique or carefully fit in.