Code:

#define MCP(m) (uint16_t)(((m & 0xF8) << 8) | ((m & 0xFC) << 3) | (m >> 3))
static const uint16_t mono_palette[256] PROGMEM = {
MCP(0x00),MCP(0x01),MCP(0x02),MCP(0x03),MCP(0x04),MCP(0x05),MCP(0x06),MCP(0x07),MCP(0x08),MCP(0x09),MCP(0x0a),MCP(0x0b),MCP(0x0c),MCP(0x0d),MCP(0x0e),MCP(0x0f),
MCP(0x10),MCP(0x11),MCP(0x12),MCP(0x13),MCP(0x14),MCP(0x15),MCP(0x16),MCP(0x17),MCP(0x18),MCP(0x19),MCP(0x1a),MCP(0x1b),MCP(0x1c),MCP(0x1d),MCP(0x1e),MCP(0x1f),
MCP(0x20),MCP(0x21),MCP(0x22),MCP(0x23),MCP(0x24),MCP(0x25),MCP(0x26),MCP(0x27),MCP(0x28),MCP(0x29),MCP(0x2a),MCP(0x2b),MCP(0x2c),MCP(0x2d),MCP(0x2e),MCP(0x2f),
MCP(0x30),MCP(0x31),MCP(0x32),MCP(0x33),MCP(0x34),MCP(0x35),MCP(0x36),MCP(0x37),MCP(0x38),MCP(0x39),MCP(0x3a),MCP(0x3b),MCP(0x3c),MCP(0x3d),MCP(0x3e),MCP(0x3f),
MCP(0x40),MCP(0x41),MCP(0x42),MCP(0x43),MCP(0x44),MCP(0x45),MCP(0x46),MCP(0x47),MCP(0x48),MCP(0x49),MCP(0x4a),MCP(0x4b),MCP(0x4c),MCP(0x4d),MCP(0x4e),MCP(0x4f),
MCP(0x50),MCP(0x51),MCP(0x52),MCP(0x53),MCP(0x54),MCP(0x55),MCP(0x56),MCP(0x57),MCP(0x58),MCP(0x59),MCP(0x5a),MCP(0x5b),MCP(0x5c),MCP(0x5d),MCP(0x5e),MCP(0x5f),
MCP(0x60),MCP(0x61),MCP(0x62),MCP(0x63),MCP(0x64),MCP(0x65),MCP(0x66),MCP(0x67),MCP(0x68),MCP(0x69),MCP(0x6a),MCP(0x6b),MCP(0x6c),MCP(0x6d),MCP(0x6e),MCP(0x6f),
MCP(0x70),MCP(0x71),MCP(0x72),MCP(0x73),MCP(0x74),MCP(0x75),MCP(0x76),MCP(0x77),MCP(0x78),MCP(0x79),MCP(0x7a),MCP(0x7b),MCP(0x7c),MCP(0x7d),MCP(0x7e),MCP(0x7f),
MCP(0x80),MCP(0x81),MCP(0x82),MCP(0x83),MCP(0x84),MCP(0x85),MCP(0x86),MCP(0x87),MCP(0x88),MCP(0x89),MCP(0x8a),MCP(0x8b),MCP(0x8c),MCP(0x8d),MCP(0x8e),MCP(0x8f),
MCP(0x90),MCP(0x91),MCP(0x92),MCP(0x93),MCP(0x94),MCP(0x95),MCP(0x96),MCP(0x97),MCP(0x98),MCP(0x99),MCP(0x9a),MCP(0x9b),MCP(0x9c),MCP(0x9d),MCP(0x9e),MCP(0x9f),
MCP(0xa0),MCP(0xa1),MCP(0xa2),MCP(0xa3),MCP(0xa4),MCP(0xa5),MCP(0xa6),MCP(0xa7),MCP(0xa8),MCP(0xa9),MCP(0xaa),MCP(0xab),MCP(0xac),MCP(0xad),MCP(0xae),MCP(0xaf),
MCP(0xb0),MCP(0xb1),MCP(0xb2),MCP(0xb3),MCP(0xb4),MCP(0xb5),MCP(0xb6),MCP(0xb7),MCP(0xb8),MCP(0xb9),MCP(0xba),MCP(0xbb),MCP(0xbc),MCP(0xbd),MCP(0xbe),MCP(0xbf),
MCP(0xc0),MCP(0xc1),MCP(0xc2),MCP(0xc3),MCP(0xc4),MCP(0xc5),MCP(0xc6),MCP(0xc7),MCP(0xc8),MCP(0xc9),MCP(0xca),MCP(0xcb),MCP(0xcc),MCP(0xcd),MCP(0xce),MCP(0xcf),
MCP(0xd0),MCP(0xd1),MCP(0xd2),MCP(0xd3),MCP(0xd4),MCP(0xd5),MCP(0xd6),MCP(0xd7),MCP(0xd8),MCP(0xd9),MCP(0xda),MCP(0xdb),MCP(0xdc),MCP(0xdd),MCP(0xde),MCP(0xdf),
MCP(0xe0),MCP(0xe1),MCP(0xe2),MCP(0xe3),MCP(0xe4),MCP(0xe5),MCP(0xe6),MCP(0xe7),MCP(0xe8),MCP(0xe9),MCP(0xea),MCP(0xeb),MCP(0xec),MCP(0xed),MCP(0xee),MCP(0xef),
MCP(0xf0),MCP(0xf1),MCP(0xf2),MCP(0xf3),MCP(0xf4),MCP(0xf5),MCP(0xf6),MCP(0xf7),MCP(0xf8),MCP(0xf9),MCP(0xfa),MCP(0xfb),MCP(0xfc),MCP(0xfd),MCP(0xfe),MCP(0xff)
};

And then changed you 's' code to use it: