How do you draw the lewis dot structure for glutaric acid, C5H8O4

An organic acid is COOH in this case there are two carboxylic acid groups so the structure is:
- C5H8O4
- C3H6(COOH)2
- HOOC-C3H6-COOH
- HOOC-CH2-CH2-CH2-COOH

The COOH is a Y shape with the C in the middle and 2 O's the ends and an angle near 120o, as it's actually -COO^- and H^+
The angle between successive carbons is 109.5%, giving the molecule a chinked shape in the middle.
All the bonds are covalent (sharing electrons to complete shells).

HOOC-CH2-CH2-CH2-COOH
The -COOH is a standard notation for an organic acid which is really O=C-OH which has a Y-shape (120° bond angle.)