The win means Llandovery are three points behind current third place Llanelli with both teams having played 18 games apiece. With Pontypridd destined for the top spot, Bedwas and Llanelli are currently in the box seat to secure the two play-off spots but on their current run, Llandovery may well push the Parc y Scarlets club close.
Their latest win saw the Drovers expose the defensive frailties of the league's bottom side though Swansea did stay in contention for much of the first 20 minutes.
Indeed the home side had actually led 8-5 at one stage, fly-half Nicky Thomas adding a penalty to a try from wing Richard Williams, the two scores in response to Murphy's first try of the day for Llandovery.
After that though, it went all wrong for the home side as Llandovery put their attacking game into overdrive.
Murphy added a double in quick-time to complete his hat-trick and when Sam Soul finished superbly after receiving a pass from centre Jack Roberts, the writing was on the wall for the home side.
James Garland had added a couple of conversions for a 24-8 lead at half time, one which soon grew at the start of the second half.
Adam Warren, who represented Wales U20 in the recent Six Nations, made it 31-8 as Swansea struggled to deal with Llandovery's options in attack.
Swansea's deficit did sting them into action though and scrum-half Jake Cole continued his good recent form with a first try of the day. They then narrowed the deficit when No. 8 Dan Baker crashed over but this only served to rile Llandovery further.
Replacement flanker Shaun Miles, centre Jack Roberts and Soul added further scores to maintain their play-off push.
The Drovers next face Bridgend at the Brewery Field on Saturday while Swansea host Bedwas on Wednesday.
Lewis' men will be hoping they can do them a favour in that one.