If my course lies anywhere within 30 degrees adjacent to the 'direct entry' sector borders, do I fly the holding pattern as depicted below?
To add to Michael Hall's answer, the direct entry is the one where you get straight on to the "racetrack" with minimum maneuvering and that is possible from anywhere within the direct entry sector. The other two entries involve initial maneuvering "off the racetrack" so to speak.
That entry diagram is a procedural convention, not a hard regulation you must follow exactly. The whole area is protected airspace, so it's not all that critical that you fly exactly this or exactly that as long as you stay in the protected airspace. You'll get dinged on a check ride for using a bad entry (using a sector's procedure while significantly outside of the boundary of that sector), but ATC would never bust you because you didn't follow the entry protocol perfectly, as long as you didn't leave the protected airspace and you got established properly without too much meandering around.