No. You cannot switch the genders of common nouns like that. "A job" in French is always masculine, even if most of the people in the field are feminine. The word « travaille » is actually a conjugation of the verb « travailler » for the third-person singular.
"My soeur a un travail" is different from is different from "J'ai un petit travail pour vous". The first sentence implies a position, a post; the second a one-off task. Just as "travail" works for both in French, so "job" works for both in English.