Labuschagne made 126 as the Bulls posted 260 on Saturday at the Gabba.
SA crashed to 135 all out in just 26.1 overs, with Swepson claiming a brilliant 7-28 from 7.1 overs.
His performance broke the list A bowling record for best match figures for Queensland, which was previously set by Carl Rackemann in 1988-89 when he took 7-34.
"In my first over, I felt like it (the ball) landed nicely and spun. The rest is all a bit of a blur, to be honest," Swepson said post-match.
"It was just one of those days where everything clicked."
SA opener Mackenzie Harvey was the sole South Australian to offer resistance, top-scoring with 72 from 66 deliveries.
Alex Carey made 36 from 40 balls - he was only other South Australian to reach double figures.
Earlier, Labuschagne dominated the Bulls' innings with his stellar century.
Queensland were wobbling at 3-41 in the 11th over after losing Sam Heazlett (three), Hugo Burdon (10) and Jimmy Peirson (four).
But Labuschagne was superb in his 137-ball knock, hitting 11 fours and a six.
Labuschagne found an important ally in Lachlan Hearne - the pair steadied with a 92-run stand for the fourth wicket.
The partnership ended when Hearne, who didn't strike a boundary in his 41 from 62 balls, fell to SA skipper Nathan McSweeney (1-45).
Hugh Weibgen made 26 from 35 balls but it was Labuschagne who controlled the innings until dismissed in the 48th over.
The Australian star was the third victim of legspinner Lloyd Pope, who finished with 3-53 from 10 overs.
Henry Thornton (2-48) and Nathan McAndrew (2-65) were other multiple wicket-takers.
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