That’s a nice one, thanks for posting the link! I like that it included both names for the notes (crotchet and quarter note, etc.)
Here’s one that I’ve used with my students as a supplement to their lesson books (I teach private lessons). Just the first 7 pages or so covers the treble and bass clefs, although the whole packet is nice:
http://pianodiscoveries.ca/images/BarnyardFriends/workbook.pdf
It uses a slightly different approach to drawing the treble clef.
I personally draw mine in a completely different manner from both of these PDFs! 
So whatever works with your kids, go for it! There’s not really a stroke order or anything… but, I like how the link you have starts on the G line and the one I posted finishes on the G line. Either one will help reinforce that the treble clef is also called the “G clef” and give a reference point for finding notes on the staff.
