I consider myself still a very big NOOB but here goes…
IIRC my stats are:
Strength - Full ( so with my Dragon bone axe + Legendary Shield its 60 + 60 dmg )
Vitality - To the perk that diminishes the weather effect (although it does not seem to work?)
Grit - I play on a private PVE server where stamina costs are adjusted VERY low so 0 in ( help allot!)
Accuracy - Is at the first perk
Encumbrance - the rest basically
I wear the advanced armorers bench perfect gear, Medium Vanir mixed with medium Aqualonian (DLC) for the heat.
And I use roasted haunch and aloe soup cos 1 poison hit hurts ALLOT.
Ok so this is obviously allot easier due to the server with the low stamina costs and you would prob have to walk around sideways allot more to regen stamina. But the fight is basically power strike 3 times and just as she starts to recoil for a normal poison hit I dodge sideways and walk around her. If she looks like she is gonna do her new tail whip thing I walk further back and wait till she starts spewing green vomit and go in for 1 to 2 full power combos. Rinse and repeat.
Hope that helps. And have fun!
EDIT: Just did it again and I must be honest the low stamina costs makes it allot easier. I hope that I can convince our admin to do an adjustment for that added strategic side. But I did follow my own tips and I believe even with normal or close to normal stamina costs it may get you the win. Really hope it helps.