To answer my own question, everyone in the group needs to sketch.
The 3rd mission is called The Ecstasy of Relief, you need to sketch the Scale of Veeshan and you need High Quality Sketching Tools. Then deliver the completed sketch to Y'ssuria.
The reward is Cloak of the Elder Drake
MAGIC ITEM LORE ITEM NO TRADE
Slot: BACK
AC: 21
STR: +16 DEX: +16 STA: +16 WIS: +16 INT: +16 AGI: +16 HP: +265 MANA: +265 ENDUR: +265
SV FIRE: +18 SV DISEASE: +18 SV MAGIC: +18 SV POISON: +18
Stun Resist: +3%
Recommended level of 75. Required level of 71.
Focus: Nhyalea's Fury
WT: 1.3 Size: SMALL
Class: ALL
Race: ALL
Slot 1, Type 7