From the uppermost (S) node divide into two branches:
The softly-worded call/\is specifically uttered when she finds love
You could subdivide the left into Det and N-bar (N'), then the N-bar into modifying adjective and head noun blah blah blah etc, but it'll be easier to just have a 3-branch NP division sprouting down from the node that is forming at the bottom of the left-hand NP branch (see above), resulting in a terminal/base "opened umbrella" NP sheltering: Det-ADJ-N (/l\).
On the right-hand side, you will divide from the predicate node into VP and subordinate/adverbial branches. The left-hand branch can terminate in something like AUX-V (I'm not bothering with the adverb 'specifically', as it could be omitted or moved e.g. to the start of the sentence), whilst the right will sub-branch into subordinator on the left, and S (sentence again! Embedded!) on the right. Finally, this S sub-branches into NP and predicate.
I've been pretty loose with the terms above, and would actually find it quite difficult myself to draw a formally labelled tree diagram (mainly because I haven't (wanted to) study any formal system of syntactic analysis in any great depth - I prefer to just come to an understanding in my head about where the divisions and groupings lie in a sentence); and even once you've settled on a labelling system, you then have all the fun of getting the angles and spacing of the branches just so, and calculating the optimal branch lengths etc etc. (Depending on the notation and levels you use, the base of the tree may not be level on left and right: the right side may progress quite a bit deeper than the left when there is a lot of embedding. Visually it is of course nice to have a level base terminating in the actual sentence's words themselves

). Nightmare, eh!!
And obviously it would be very difficult to attempt to draw one on Dave's, though I do have an idea of how it might be possible to sort of "draw" a "tree" diagram:
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS
NPNPNPNPNP(SUBJ)NPNPNPNPNP/PREDPREDPREDPREDPREDPREDPRED
etc.)
Good luck!