Cabal has an interesting etymology:http://www.etymonline.com/index.php?allowed_i...
1520s, "mystical interpretation of the Old Testament," later "society, small group meeting privately" (1660s), from French cabal, in both senses, from Medieval Latin cabbala (see cabbala). Popularized in English 1673 as an acronym for five intriguing ministers of Charles II (Clifford, Arlington, Buckingham, Ashley, and Lauderdale), which gave the word its sinister connotations.
Rather than Verschwörer - which can also mean a single individual who is part of a group - I would probably see this as Geheimbund/Verschwörergruppe.
My "Cassell's," btw, has "cabal" as
1. die Kabale, Intrige, Ränke (pl.
), Machenschaften; die Clique, der Geheimbund, Klüngel
Ränke schmieden, intrigieren, sich verschwören.
Man sollte hier zumindest unterscheiden zwischen Nomen und Verbum, denke ich.