The Hebrew names of the Chumashim are usually referred to as בראשית שמות ויקרא etc. but the English names do not correlate with these names literally. The English names are Exodus, Numbers etc not Names, Desert (or Wilderness). While the Hebrew names are obviously based on the first words (or Parsha) of the sefer, where did the other names originate from and why don't we just use the English translation of the Hebrew version?
If you look in midrash and other early sources, you will actually find the following Hebrew names for the 5 books:
- Sefer Bereshit
- Sefer Hageulah
- Toras Kohanim
- Chumash Hapekudim
- Mishneh Torah
These ancient Hebrew names correspond exactly with the English names you cited. For some reason, in modern Jewish speech the names based on the first word have become more popular. However, the names in English, deriving from the Septuagint, possibly originated from these ancient Hebrew names of these books.