Poor quality pdf upload

I’m attempting to upload a free printable pdf created in Illustrator CS5. The file looks fine when I save it, but when I attach it, linked to the media file, and open it in the post preview, it displays with really poor resolution and off coloring. I’m using Safari to view.

I’ve tried saving as both RGB and CMYK profiles to see if that makes a difference as well as a variety of pdf saving presets (smallest file, press quality, high quality print, etc). Someone please help ??