In-form McGuire put the reigning champions ahead in the fourth minute before conjuring two brilliant long-range efforts.
Ryan Hall joined McGuire in claiming a treble and with Rob Burrow, Lee Smith and Brett Delaney also touching down, the Headingley faithful departed in buoyant mood ahead of next weekend's trip to the capital.
Much has been made of Leeds's unprecedented feat of successive Super League titles in the past three seasons, yet their desire to win the cup for the first time since 1999 has been obvious this year.
Leeds-born McGuire got his side off the mark when he played a one-two with Smith before scampering clear.
Brian McClennan's men began to build up a head of steam and their second try arrived when Brent Webb's clever pass sent Hall over in the left corner.
Leeds had their third try when Keith Senior showed intelligence to send Burrow darting over from close range before the Dragons' defence was breached again as Webb and Hall combined again.
Catalans finally woke up in the 25th minute when Casey McGuire burrowed his way over from close range and Thomas Bosc added the conversion.
Yet the momentum remained largely with Leeds and McGuire raced clear from inside his own half to outstrip the visiting defence and cross.
Smith then went over shortly before the break in the right corner for Leeds's sixth try – the only score which Kevin Sinfield failed to convert.
Hall struck again in the 48th minute when he dived over in the left corner for his hat-trick and Sinfield added the extras.
Leeds had their eighth try when Brett Delaney pounced on a loose ball to touch down, and Sinfield again converted.
Catalans remained physically imposing but could not come close to matching Leeds's skill levels.
McGuire collected a pass from Senior and sprinted 70 metres for another brilliant individual effort between the posts. Sinfield converted for his eighth goal from nine attempts as Leeds left their French visitors, who had David Ferriol sin-binned late on, utterly outclassed.
Leeds Rhinos: Webb, Smith, Senior, Delaney, Hall, McGuire, Burrow, Leuluai, Buderus, Bailey, Clarkson, Jones-Buchanan, Sinfield. Substitutes: Lauitiiti, Diskin, Eastwood, Kirke.
Catalans Dragons: Stacul, Bell, Carlaw, Walker, Vaccari, Bosc, Sherwin, Ferriol, McGuire, Casty, Elima, Gossard, Johnson. Substitutes: Touxagas, K. Bentley, Gigot, Sa.
Referee: J Child (Dewsbury).