You can sew it by machine but if you use whole hexagons, you will be joining everything with "Y" seams, which can be tricky. I have seen patterns where they use 1/2 hexagons, sew them together in rows with the matching colored halves in the next row. Looks a little different because of the extra seam but it gives exactly the same pattern in the end.
Here's a link to instructions showing "Y" seam method:
http://www.sharonschamber.com/free%2...owergarden.pdf
And here is a video showing the 1/2 hexie method:
http://www.youtube.com/watch?v=F7c1ewoQV24
She is making a scrappy one but you could make it more planned it you want to.