No, that's not what it means. The graph is not saying "Gem X at Y DPS" It reads as "When you gain X amount of STR/Haste you will do Y amount of DPS" if that makes any sense (not sure how to explain that).
As you can see from your results:
+40 STR < +40 Haste
+60 STR = +60 Haste
+100 STR > +100 Haste
The purpose is just to show that our str/haste stat weights aren't exactly linear and start to overtake each other at certain points.
The amount of DPS you currently do has no relation to the value of your stat weights. Your stat weights will change constantly as your stats change, not your DPS.
That graph looks like it is produced with 100 iterations or so, definitely not enough. Try increasing that to 20'000, which will smooth out the strength plot, and show more clearly the places where haste deviates from a linear increase.
And when gemming you need to remember that you get twice the amount with secondary stats than primary stats. So strength's marginal value needs to be at least twice that of haste.